1. Methods
Results
Conclusions
Significance
LimitationsPurpose
1
Bill Coburn, MA, ATC, CSCS, 1
Keith Vanic, PhD, ATC, 1
Gerald Rozea, PhD, ATC, 1
John Hauth, EdD, ATC, 2
Doug Burns, MS, 3
Kevin N. Waninger, MD, MS,
1
East Stroudsburg University, East Stroudsburg PA, 2
DeSales University, Center Valley PA, and 3
St. Luke’s Hospital & Health Network, Bethlehem PA
Susceptibility Of Air Displacement Plethysmography To Intentional Error:
The Effect Of Carbonated Beverages And Sodium Bicarbonate On Percent
Body Fat Estimation In The Bod Pod®
The BOD POD® air displacement
plethysmograph is one method
used in the appeals process for
weight certification in wrestling.
It is a valid measure when body
hair, clothing, and temperature
are controlled. Body density is inversely proportional
to the percentage of body fat, and excess gas in
the gastrointestinal tract will spuriously skew the
equations for
calculating body
fat percentage,
giving a lower body
density and thus
higher calculated
percent body fat.
It is the intent of
this investigation to
evaluate the effects
of gas producing
beverages on
the accuracy of
measurement of
percent body fat as
calculated by the
BOD POD®.
Ten college students (age 22-32) had baseline
BOD POD® for %-body-fat composition, then were
randomized to receive either a 12-ounce can of
Sprite® or one sodium bicarbonate tablet (Alka-
Seltzer®). CO2 evolution from a soft drink or Alka
Seltzer tablet accounts for about 150-200 ml. of
additional gas. Each subject then underwent BOD
POD® testing at 10 and 30 minutes post-beverage
consumption. After 48 hours, the entire
procedure was repeated with the
other carbonated beverage. Repeated
measures ANOVA were conducted
in SPSS with beverage and time as
within-subject variables. All 10 subjects
completed both stages of the study.
Mean %-body-fat composition with Sprite® consumption raised
from baseline +0.50% at 10 minutes and +0.47% at 30 minutes, and
with Alka-Seltzer® consumption raised from baseline +0.29% at 10
minutes and +0.22% at 30 minutes. These values were not significant.
The body fat compositions in our subjects1.
was fairly high in comparison to the wrestling
population (who may average 8-12% in the middle
weight classes), and the relatively small change in
apparent body density generated by the additional
200 ml. of gas in larger subjects may have a
smaller impact on the calculated %-body-fat than
in a leaner population.
This study may be underpowered to affect body fat2.
calculations and reach statistical significance.
The body wall is flexible, and the gas in the3.
GI-tract may be no less compressible than in
surrounding air; thus the gas may not contribute to
an increased BOD POD-measured volume which
would yield an increased apparent density.
Percent body fat estimation using the BOD POD®
in subjects who ingest Sprite® or Alka-Seltzer® was
not affected at the p≤.05 level. Carbonated beverage
intake did not alter BOD POD® testing results.
Carbonated beverage intake increasing
gastrointestinal gas content did not alter BOD POD®
testing results for percent body fat estimation.
Sprite Age Height Weight
Baseline
%-body-fat
10 Min
%
30 min
%
1 32 71.25 228.7 28.6 29.5 28.4
2 23 68.5 155.6 32.5 33 33
3 23 67.25 188.3 32.6 32 32.5
4 24 65.5 119.6 21.4 20.8 22.1
5 29 69.75 189.9 19.5 22.6 22.1
6 23 67.25 144.6 25.1 22.8 23.4
7 23 70.5 192.6 31.7 34 33
8 24 72.5 193.6 28.1 27.8 27.8
9 24 68.5 196.8 23.6 25.3 25.7
10 23 66.5 144.9 27.4 27.7 27.2
Mean 24.8 68.75 175.46 27.05 27.55 27.52
Std. Dev. 3.120 2.227 32.808 4.599 4.627 4.280
Alka
Seltzer
Age Height Weight
Baseline
%-body-fat
10 Min
%
30 min
%
1 32 71.25 228.5 27.8 28.9 28.9
2 23 68.5 156.4 32.2 33.9 33.6
3 23 67.25 186.3 33.2 33.3 33.4
4 24 65.5 120.4 20.8 21.3 20.4
5 29 69.75 188.8 23.6 23.9 23.2
6 23 67.25 140.8 23.1 24.1 24.8
7 23 70.5 193.5 36.4 34.7 34.2
8 24 72.5 194.4 26 26.9 26.7
9 24 68.5 198.8 27.3 26.6 27.1
10 23 66.5 145.9 27.6 27.3 27.9
Mean 24.8 68.75 175.38 27.8 28.09 28.02
Std. Dev. 3.120 2.227 33.011 4.885 4.584 4.635
Table 1. Sprite®
Results Table 2. Alka-Seltzer®
Results